What is a power-frequency transformer? And what’s the difference between a power-frequency transformer and a regular transformer?

Power-frequency transformers, also known as low-frequency transformers, are distinguished from high-frequency transformers used in switch-mode power supplies. Historically, power-frequency transformers were widely employed in conventional power supplies, which relied on linear regulation to maintain stability—hence the term "linear power supplies." The term "power frequency" typically refers to the frequency of mains electricity, which in China is 50 Hz, though other countries use 60 Hz. A transformer capable of altering the voltage of AC power while maintaining this specific frequency is precisely what we call a power-frequency transformer.

The Role of High-Frequency Transformers _ Where Are High-Frequency Transformers Used?

Currently, switch-mode power supplies typically use a half-bridge power conversion circuit, which includes components like a high-frequency transformer and transistors. When the circuit operates, the transistors alternate between conducting states, generating high-frequency pulses at a rate of 100 kHz. These pulses are then stepped down via the high-frequency transformer, ultimately producing a lower-voltage AC output. The exact output voltage level is determined by the turns ratio of the individual windings in the high-frequency transformer. In most designs, three separate transformers are employed: the main transformer, the driver transformer, and the auxiliary transformer. Each of these transformers has its own specific design specifications and critical functions, making them all indispensable to the overall operation of the system.